Dental appliances or prostheses, such as removable orthodontic devices or partial dentures, are typically held in place by securing the appliance to adjacent teeth. An Adam's, ring or "C" clasp is commonly used for this purpose. The clasp is a wire structure which wraps around adjacent teeth, generally along the gum line, in order to provide stable and reliable attachment of the dental appliance.
However, this configuration does not reliably secure a removable dental appliance and can irritate the gum tissue. Further, healthy teeth tend to decay due to contact with the metal clasps and because of the mechanical forces transmitted by the appliance to the health teeth.
In certain circumstances, the crown of a tooth is prepared whereby a portion of the crown is removed and a dental crown is place on the tooth to provide an undercut surface. This method, however, is destructive to the tooth and expensive. For example, U.S. Pat. No. 4,445,861 issued to Klepacki on May 1, 1984 discloses a denture support system where the canine teeth are modified by creating a substantially horizontal ledge, from 0.50 to 0.75 mm wide.
Alternatively, U.S. Pat. No. 4,768,957 issued to Segura on Sep. 6, 1988, discloses a two-part metal coupling system for retaining dentures. The male portion 5 of the couple is glued to an inside face of an anchor tooth. The denture is attached to a female portion 6, which in turn engages directly with the male portion 5. However, the metal coupling system of Segura is more costly to manufacture and the cast metal tab 4 secured to the tooth 1 may cause decay of an otherwise healthy tooth, as discussed above. Further, the metal coupling system and associated dental appliance are significantly larger than the dental appliance system of the present invention.
The present invention addresses these and other problems associated with the prior art.